This paper analyzes and measures the value that American private banks added as directors of non financial companies. Using data between 1874 and 1913, and an event study from 1906, I find that bank directors added about 20% of a firm’s market capitalization. Collusive practices encouraged by private banks accounted for 65% of this value, and were the equivalent of creating a three player market among railroads. About 35% of the value added by banks came from better governance. I argue that although policymakers were partly right in sidelining private banks as activist investors, this helped entrench managers. JEL: G21, G24, G3, K21, L41, N21. Keywords: Antitrust; Collusion; Corporate Governance; Financial History.